Net Free Vent Area NFVA 1:150 rule

The Convective Engine: Stack Effect Physics, Net Free Vent Area (NFVA), and Intake-to-Exhaust Equilibrium in Tropical Roofs

• September 26, 2026
• admin

In steep-slope building science, a common misconception is that a roof’s sole function is to shed water. Property owners and builders often focus entirely on the exterior skin—the shingles, flashings, and underlayments—while treating the attic or rafter cavity beneath as dead, unmanaged space. In peninsular India, this omission causes severe building performance failures. During the …